圆的切线是初中数学的重点内容之一,也是中考的主要考察对象.本文举例介绍证明圆的切线的几种常用策略.一、当讨论的问题涉及圆的半径r及圆心到直线的距离d这样的数量关系时,往往可以 The tangent of the circle is one of the key contents of mathematics in junior high school and is also the main object of study in the middle school entrance examinations.This paper introduces several commonly used strategies to prove the tangent of a circle.When the problems discussed involve the circle radius r and the distance d Such a quantitative relationship can often be